This application relates to a method for objectively determining chronic pain in individuals.
Humans (as well as animals) suffer from two types of pain. Transitory pain, caused by external factors such as impacts, heat, etc. and injuries to tissue caused thereby, or by certain illnesses, can last for short moments to longer periods of time. It typically lasts until the effect on the person's tissue from injury or illness subsides, e.g. until a wound or burn, for example, has partially or fully healed. Humans also suffer long-term or chronic pain, which may or may not be the result of external factors and which typically persists for indeterminate lengths of time. Chronic pain can be debilitating and can prevent the person suffering such pain from leading a normal life, pursuing an occupation, performing many routine activities, and the like. Persons suffering chronic pain are often entitled to compensation from an insurance company, an employer, the government, individuals who negligently or intentionally inflicted the pain, etc. In the past, it was most difficult if not impossible to objectively determine the chronic pain allegedly suffered by a person. Making this determination, however, is important in order to fairly and adequately compensate the pain sufferer.
The root for the problem of objectively determining the presence of chronic pain and/or to quantify it is that pain is perceived by the brain, and there are presently no feasible tests or procedures which can objectively determine if chronic pain is present and, if so, the magnitude thereof. As a result, persons, such as physicians, psychologists, technicians and the like, had to principally rely on a subjective evaluation of the chronic pain by the patient. This is a difficult and highly inaccurate task, leading to unreliable results.
An individual's perception of chronic pain may be incorrect due to a variety of factors, such as his/her mental and/or emotional state, an objectively incorrect perception of the pain by the individual's brain, variations in pain tolerances by individuals, etc.
In addition, the pain sufferer may be motivated to embellish or diminish the chronic pain for purposes unrelated to the pain itself. Thus, an individual might exaggerate, embellish or completely fabricate the presence, description and/or magnitude of chronic pain. Most often this occurs when an individual seeks to be compensated by a third party for the chronic pain he asserts to suffer. The individual may exaggerate or fabricate the chronic pain because he believes this may yield a higher payment from an insurance company, may lead to a higher settlement of a dispute, may assist the individual in prosecuting a lawsuit, may gain sympathy from others, and the like. Individuals also might minimize the chronic pain suffered by them, for example, in order to qualify for a position he/she seeks where chronic pain might be an obstacle.
The processing of insurance claims for compensation as a result of debilitating chronic pain is probably the most frequent occurrence requiring a determination of the presence and/or magnitude of chronic pain. Such claims may be for a one-time lump sum compensation, or for lifelong support as a result of actual, embellished or entirely fabricated assertions of high levels of chronic pain and the disabilities that can flow from them. Since a significant segment of the population suffers from chronic pain, the liabilities incurred by insurance companies and others obligated to compensate the sufferers are very large and typically lie in the billions of dollars per year nationwide.
Persons seeking compensation who do not suffer chronic pain, or suffer it at a non-debilitating level, would, if the claim is accepted, receive unfair compensation to which they are not entitled. This in turn burdens insurance companies and those insured by the insurance companies, because excessive or fraudulent claims lead to higher insurance premiums.
Up to now it has not been feasible to objectively determine the presence and/or amount of chronic pain, in an objective and reliable manner that is comparable, for example, to the way in which the cholesterol level in a patient can be determined with a simple blood test. Instead, claims for compensation due to chronic pain were in the past processed by persons who had experience in such matters. They looked at a variety of factors which can suggest the presence or absence and/or the level of chronic pain based on the patient's current behavior, background, personal and medical history, possible motivations for embellishing or fabricating their description of the chronic pain suffered by them, etc. Although such evaluations of claims are helpful, in that at least gross misstatements, exaggerations and outright untruths by the patient can sometimes be observed or detected, they are, at best, nonscientific, subjective and quite unreliable. As a result, a patient who suffers chronic pain might be wrongly judged as not having it, while another person who cleverly postures might be found to suffer such pain and be unjustifiably compensated.
It is well known that the presence of chronic pain is perceived and established in the brain. It has been suggested to more objectively determine the presence and/or level of chronic pain by observing brain activities that might evidence the presence of chronic pain and/or the level of such chronic pain.
U.S. Pat. No. 6,018,675 (Apkarian), for example, discloses to measure pain in a patient by applying a variable intensity pain stimulus in a time-dependent manner during which the patient's brain responses are recorded using imaging (for example, a functional MR) while the patient indicates the level of discomfort using a perceptometer or other similar pain rating device operated by the patient as the pain stimulus is applied and varied. The pain rating is correlated with the imaging results using a quantitative analysis to characterize the brain's representation of this pain. Color overlays are generated on high resolution anatomical images (MR or other modality) of the brain summarizing the calculated pain-related analysis information.
The Apkarian patent states that, during an examination, the patient is subjected to variable pain over a period of time during which brain responses of the patient are objectively imaged and during which time subjective indications of the level of discomfort of the patient are recorded. Thereafter, the subjective indications of the level of discomfort are correlated with the objectively imaged brain responses in order to characterize the brain's representation of the pain in relation to the patient's perception and irrespective of the details of the stimulus, which may be only weakly related to the perception. In this method, the patient may be externally manipulated in order to inflict a variable pain. Such manipulation may include the movement of a leg in the case of a patient experiencing chronic back pain. In other cases, the variable pain may be provided by the application of an external stimulus such as a thermal stimulus. In all cases, the stimulus perturbs the patient's pain perception and the patient himself/herself provides the perception signal used for analyzing the brain images.
The patient's subjective indications of pain are compared to the brain activities of a group of persons to whom the same pain stimuli were applied. Thus, the Apkarian patent further states that a large number of persons having the same pain-causing condition are tested using the above techniques in order to obtain an “aggregate” value for the condition. This sampling may also include persons who do not have the pain condition to test the reliability of the results obtained. For example, in order to establish an “aggregate” value of the brain images to be expected for a person having a lower back pain condition, several persons are tested to obtain brain images for different levels of pain inflicted on them, for example by raising a person's leg to different angles to the horizontal. That is to say, with a person placed in a supine position, each leg of the person can be raised to different angles to the horizontal, for example in 5° increments. The brain images which are taken for each angular increment are then correlated with the pain rating indicated by that person. The resultant brain images relative to an indicated pain level may then be aggregated for these persons in order to establish an “aggregate” value to be expected for different levels of pain indicated by the rating device.
Once the “aggregate” value has been established, a patient may be subjected to a similar protocol to obtain his/her rating of pain for each angular increment of the leg relative to the horizontal. The brain image of the patient corresponding to the pain rating can then be compared to the aggregate brain image to be expected for the given pain rating. Deviations of the actual brain image from the expected aggregate brain image can then be used as objective evidence of feigned pain.
Thus, the Apkarian patent discloses a method of measuring brain activity in response to a number of pain stimuli successively applied to the patient. Although this approach may be helpful in discerning the pain generated by a number of pain stimuli, the method taught in the Apkarian patent does not and cannot distinguish between chronic pain and transitory pain and cannot establish the presence and/or magnitude of chronic pain on an objective basis.
As a result, these past attempts have not been adopted because of their questionable reliability, accuracy and/or practicability. Thus, there exists a need for a method to objectively determine chronic pain and chronic pain levels with a high degree of accuracy and reliability.